Mechanical seals for pumps may encounter some faults and problems during operation, which may be caused by no normal operation during installation. Therefore, various inspections must be carried out during installation, mainly including: mechanical seals for pumps may encounter some faults and problems during operation
1. The hole diameter and depth dimension of the mechanical seal cavity for the pump shall be consistent with the dimension on the seal assembly drawing, with a general deviation of ± 0.13MM; The dimensional deviation of shaft or shaft sleeve is ± 0.03mm or ± 0.00mm-0.05. Check the axial displacement of the shaft, and the total axial displacement shall not exceed 0.25mm; The radial runout of the shaft is generally less than 0.05mm. Excessive radial runout may cause: shaft or shaft sleeve wear; Leakage between sealing surfaces increases; The vibration of the equipment is intensified, thus reducing the service life of the seal.
2. Check the bending of the shaft. The maximum bending of the shaft shall be less than 0.07mm. Check the runout of the surface of the sealing cavity. The runout of the surface of the sealing cavity shall not exceed 0.13MM. If the surface of the sealing cavity is not perpendicular to the shaft, it may cause a series of faults of the mechanical seal. Because the sealing gland is fixed on the sealing gland by bolts, the excessive runout of the sealing cavity causes the inclination of the gland installation, which in turn causes the inclination of the sealing static ring, resulting in the abnormal shaking of the whole seal, which is the main cause of micro vibration wear. In addition, the wear of the mechanical seal and the auxiliary seal of the shaft or shaft sleeve will also intensify, Moreover, the abnormal shaking of the seal will also cause the wear and fatigue of the metal bellows or transmission pin, resulting in the premature failure of the seal.
3. Check the alignment between the cavity hole of mechanical seal for pump and the shaft, and the misalignment shall be less than 0.13MM. The misalignment between the sealing cavity hole and the shaft will affect the dynamic load between the sealing surfaces, so as to shorten the operating life of the seal. To adjust the alignment, better alignment can be obtained by adjusting the gasket between the pump head and the bearing frame or reprocessing the contact surface.
At present, under the requirements of production safety and environmental protection, mechanical seals have been used more and more widely. Mechanical seals are used in industrial and enterprise dynamic equipment to ensure no leakage between dynamic and static sealing surfaces. There are many kinds and models of mechanical seals for industrial pumps and chemical pumps, but there are mainly five leakage points:
① Sealing between shaft sleeve and shaft;
② Sealing between moving ring and shaft sleeve;
③ Sealing between dynamic and static rings;
④ Sealing between stationary ring and stationary ring seat;
⑤ Seal the seal between the end cover and the pump body.
Post time: Dec-07-2021